In Laserite (trademark) plate making systems of the type manufactured and sold by EOCOM Corporation of Irvine, California and as disclosed in United States Application for Letters Patent, Ser. No. 758,250, filed Jan. 10, 1977, there is apparatus disclosed which is capable of registering plates of one size. A need has arisen to provide such apparatus which is capable of precisely registering plates of more than one size. There is therefore need for an improved Laserite plate making system.